angry tapir writes: "A coming revolution in 3D printing, with average consumers able to copy and create new three-dimensional objects at home, may lead to attempts by patent holders to expand their legal protections, a paper from Public Knowlege says. Patent holders may see 3D printers as threats, and they may try to sue makers of the printers or the distributors of CAD (computer-aided design) blueprints, according to digital rights group Public Knowledge."